The measurement of fluid flows is important in manufacturing, medicine, environmental monitoring, and other areas. One type of flow sensor measures the rise in temperature of a fluid flowing past a heater. Smaller temperature rises correspond to faster flow. Gases and liquids are both fluids and their flow rates can be measured by flow sensors that include temperature sensors and heaters.
Current technology provides systems and methods for producing temperature sensors and heaters on substrates using well-established semiconductor processing techniques. Those skilled in the art of semiconductor manufacturing are familiar with these system and methods such as photolithography, deposition, vapor deposition, etch, wet etch, plasma etch, reactive ion etch, as well as numerous other processes.
Many measurable fluids and gases react chemically with fluid flow sensors and bond pads because some of the sensor materials and the fluid come into contact and because they are reactive. Additionally, wire bonds made on the surface exposed to the gas or liquid being measured may interact with the flow or may be corroded by the flow material. Aspects of the embodiments directly address the shortcoming of current technology by preventing the fluid from contacting the reactive sensor materials.